Conventionally, the method for automatically controlling the running of vehicles on a road is generally classified into a "moving target" method (hereinafter, referred to as an MT method) and a vehicle-to-vehicle distance method.
The MT method comprises controlling the running of a real vehicle on a real road so as to follow an imaginary target (moving target) running on an imaginary road in a computer. That is, the MT method, as shown in FIG. 1, assumes a road 1, in the computer, equivalent to a real road and comprises setting points MTS 2 for enabling an ideal running to be achieved at a given interval on the running road 1, and running them and making control for enabling a real vehicle on the real road to follow the MT 2.
As a practical application of the MT method, there is a vehicle for sight-seeing around an exposition place. By taking it as an example, the conventional MT method will be explained below. As shown in FIG. 2, a main lane 5 is created as a loop-like lane and branch lanes 7 are created at proper intervals, each leading to a platform 6 where passengers can get on or get off the vehicle. Here, the platform 6 is typically for a station. The branch lane 7 again merges past the platform 6 onto the main lane 5. FIG. 3 is an enlarged view showing the platform 6 and branch lane 7. In FIGS. 2 and 3, reference numeral 8 represents a branching point, and 9 a merging point, 8a a decelerating lane constituting a lane from the branching point 8 to the platform 6, and 9a an accelerating lane from the platform 6 to the merging point 9.
As shown in FIGS. 2 and 3, position information equipments 10 and communications equipments are provided along the main lane 5 over a full length to communicate with the vehicles and the vehicle is operated in accordance with a target signal issued from the position information equipment 10.
In order to enable the vehicle, which leaves the platform 6 to join the main lane 5, control is made to enable the vehicle to depart from the platform 6 just in a timing to acquire the target MT 2 at the merging point 9 or all the MTs 2, which are allocated to respective vehicles to be delayed.
That is, in the conventional MT method, irrespective of whether the vehicle approaches to the running road (main lane), the target MT 2 is generated at a given interval and the vehicle is controlled enable the vehicle to follow the target M2. The MT control method above constitutes a positive control method, but it is necessary to provide the position information equipment and communications equipment over the full length of the running road. Therefore, a larger-sized computer system is required to control this.
There is an increasing demand for a long-distance non-attendant transportation system in view of a recent increase in transportation quantity and a man-power shortage. If the MT method is adopted over the full length of the long-distance running road, the equipment cost becomes vast.
On the other hand, a vehicle-to-vehicle distance control method comprises mounting a vehicle-to-vehicle distance measuring device on each vehicle and operating the vehicle, while maintaining a proper distance between the vehicles, so that any collision may be prevented from occurring. This system has been extremely high in performance in a recent advance in the laser technique and in electronic technique. The system above has only to be equipped with a measuring device for each vehicle and any equipments, as in the MT method, need not be provided over the full length of the road, so that an economic advantage can be gained in view of a long distance to be covered.
The system, however, still ensures no adequate reliability at those branching points and merging points on the running road where vehicles are closely crowded and it is necessary to perform a complex maneuver.
The conventional MT method presents the following problems because the target MT is generated at a given interval irrespective of any entry of the vehicle.
(1) If any MT control is made over the full range of the running road, it is necessary to provide the position information equipment and communication lines for an entire road. Because a larger computer is required for this control, the equipment cost becomes greater.
(2) The vehicles do not always enter or join the MT control section just in a timing to be matched to the target MT.
(3) In the case where the vehicle enters or joins in a different timing from the generation of the target MT, it is necessary to temporarily decelerate the vehicle to acquire a matching between the vehicle and the target MT. In the case where the vehicles are operated in a continuous way, it is necessary to sequentially decelerate those subsequently following vehicles in which case a cause for a disturbance is introduced in the control of the vehicles.
In the vehicle-to-vehicle distance control method, on the other hand, an associated device has only to be provided for each vehicle and it is not necessary to provide the equipments over a full length of the running road as in the MT method. Therefore, an economic advantage is gained in view of a long distance covered, but no adequate reliability is gained on the road at a branching points and merging points where vehicles are closely crowed together or a complex maneuver is necessary.
It is accordingly, the object of the present invention to provide a running vehicle control method which can make a computer compact and a cost lower, obviate the need to decelerate the vehicle upon entering or joining the target MT control section, avoid a disturbance in the control of the vehicle and ensure high reliability.